Fuel Tank build
 

Here's some things I've learned. When testing a tank under preasure.
1st you only need about 1lb of preasure. I took it to the high side of 1lb. IE the needle on a 0 to 15lb guage was just to the right of the 1lb mark and it was touching that mark.
THAT'S IT NO MORE!

My brother has a really sharp guy working for him he said if you take it to 4lbs that sucker will unzip itself. I belive him.[^]

http://www.classicmako.com/bobby/P1010111.JPG

http://www.classicmako.com/bobby/P1010114.JPG


Here's some interesting data from brother Rick.

Here is something you can show to the people that think you should
pressurize your tank to several psi for testing. I put together a quick
model and analyzed it in my finite element program (stress analysis). I
modeled it to the same dimensions as your tank and even put in the interior
baffles as they add to the rigidity of the tank. I then put a load of 1 psi
internal pressure. You can see the results. The max stress is the orange
area which equals 130,599 psi. Just so you know, the material we used
yields (permanently bends) at about 100,000 psi. I assume what is happening
is that the area that is permanently bending is small and that is why it is
not showing up. However, it probably won't take much higher pressure to
open this thing up. The orange areas show you where it will most probably
open up first.

http://www.classicmako.com/bobby/fuel%20tank.jpg

Re: Fuel Tank build
 

Gotta love CAD, Nice welds, looks great. That's aluminium isn't it? USCG won't certify stainless tanks anymore.

Re: Fuel Tank build
 

nope.. she's Stainless Steel... [img]/images/graemlins/shocked.gif[/img] [img]/images/graemlins/shocked.gif[/img] [img]/images/graemlins/shocked.gif[/img] [img]/images/graemlins/shocked.gif[/img]

Warhog.. why SS tank?

Re: Fuel Tank build
 

Yes it's ALL stainless steel. It will still have a Coal Tar epoxy coating on the outside.

Re: Fuel Tank build
 

Yeah, I had a beautifull 130 gallon belly tank that I tired to get recertified and no one would touch with a stick. And the USCG doesn't like them because the welds are prone to give out. The freak'n thing had to weigh 300lbs. [img]/images/graemlins/shocked.gif[/img]

Re: Fuel Tank build
 

I'm not sure I understand ....

Bobby .... feel like we are ganging up on ya with the questions... but the pressure testing ... is 1 "lb" (psi I assume) appropriate ?? I ask only because of what the Federal Regulation states (or at least how I read it) ....plus I know the tank builders around here all mention and build to the CG/Federal standards and they typically test to 5 psi …even mentioned on their websites

Does the 1 psi pressure test fit within the Federal requirements ? Is the caveat in #2 below ?

Maybe I don’t understand the methods of testing or the numbers being thrown around here….or maybe it has to do with the malleability of Aluminum vs Stainless?


Quote from Boatbuilder handbook
Title 33 CFR, Sections 183.501–183.590
FUEL SYSTEMS
Revised November, 2003

“FEDERAL LAW:
183.542 Fuel systems.
(a) Each fuel system in a boat must have been tested by the boat
manufacturer and not leak when subjected to the greater of the
following pressures:
(1) Three pounds per square inch; or
(2) One and one-half times the pressure created in the lowest part of the
fuel system when it is filled to the level of overflow with fuel.
(b) The test pressure shall be obtained with air or inert gas.”

Re: Fuel Tank build
 

Scott I understand your consern. Does anyone really put that much preasure on them? The guys I get my imfo from all all in the Naval Medical Reserch Facility. They build all kinds of WILD $hit. One of the guy's there said "If you put 4lbs in that sucker it will unzip itself". he's a pretty sharp guy and has fooled with this stuff a fair amount.

Here's a quote from another guy who builds fuel tanks.

Accurate Towers
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Naples Fla USA

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Re: Fuel Tank Build (warthog5) 7:43 AM 12/7/2004 Reply to this post

Warthog...

Yes 3 lbs. is ALOT, you dont need that much air at all. Just fill up the tank till it bulges a little bit, don,t over fill it at all. Use a soapy water mixture in a spray bottle to find leaks. Wow, Stainless is definate overkill. That tank will break your back. Stainless is ok for a tank but usually for hundreds of gallons. A 70 gal.
tank could have been made of aluminum and weighed less overall. The gas
pickup should be no less than 3/8ths dia. tubeing. Any less will starve your
motor and stall eventually. Do not put any back flow devises on your gas line
they tend to starve an engine as well. Use a good recomended cartrage in
line filter. The vent, nothing less tan 5/8ths hose, anything less will make it a
hard slow filling tank. Try to make your gas fill tube a straight run to make it a faster filling tank, any bends or 90 degree fills will drasticlly cut down filling of the tank. Bet you'll never try another tank again, only if you must.

Good luck... http://www.AccurateTowers.com

Re: Fuel Tank build
 

Warthog, I'm not trying to bust your nuts but I do know stainless tanks are a no no. You can do anything you like in your boat (looks great btw) and you've worked hard, but don't try and sell yourself on a tank that can't hold 4 psi.

There's a reason why you don't see stainless tanks in new boat manufacturing, and it's not becauce they're expencive.

and notice the fact that coal tar epoxy has peeled off in sheets...


every time I read ANYTHING this guy types I laugh !

warthog ?? should "bobby the butcher"...

So you never screwed up before? My guess is you got booted out of kindergarten for not playing nice.....

strick

Me, I never have..lol
This guy had such a nice boat and did good work and he makes a tank out of SS, then coats it, and tops it off with some foam. O well, everyone should know by now how to install a gas tank. Not even sure why you need to coal tar coat a tank anyways. KISS theory applys here. This tank out of the 1967 bowrider, looks to us as original, and has little pitting on the outside. It looked to just been laying in the coffin with rubber strips on it, no tar no foam.....

Agreed. I see no reason to coat a brand new fuel tank.

Live and learn here is the message. I see no reason to bad mouth Bobby. He has helped out lots of guys that have restored boats.

strick

I've made many mistakes... you ??

but,here's guy who claims to know all - a guy who works out of his backyard - making all sorts of claims - the fact is,the guy's a friggin' hck,his "work" shows it...

the first mistake was making a tank from stainless steel...

the second was failing to properly prep the surfaces

third was foam

fourth was,using that piece of wood

fifth,was him boasting and people feeding his ego...


nice boat huh ?? wonder what else will be discovered ?? fuel tank problem - problem with the paint before ?? i'm sure there's a whole lot more !!

advice from someone with limited knowledge,limited experience and poor work practices isn't usually very good,is it...

coating an aluminum fuel tank is an excellent practice - notice the word "aluminum" ??

installing a fuel tank following proper procedures is critical...

I think fuel tank installation is pretty tough really if you want it to last. When I took the tank out of my 74, most of the hold down points were at or near failure. My tank was solid but the fuel fill hose was rotted through and you could see the damage spilled gas had done to the plywood sheet under the tank, loose in two places and soft. There's a lot of motion to the ocean so over building a system to hold it in place is a really good idea. I had the tank builder add two extra brackets and I used 1 1/2" of plywood at each point, two screws instead of one + epoxy. Hopefully that will keep it there. I'm less worried about corrosion to the bare aluminum, should be good for another 40 years.

very true - people are often unaware of the "accepted" procedures...I've seen some interesting ways boat owners attempted to install fuel tanks - using pool "noodles" as a method of securing the tank...
another thing is,people are trying to cut few corners and save some money - this often leads to trouble down the line...

bottom line : this guy did a butcher job of a fuel system lay out,from the tank material on down...

Yep I've even posted many my of mistakes on the internet for all to see....you?


strick

I followed this guy's build and really liked a lot of the things he was doing at the time. You leave yourself very exposed when you basically blog an entire build and it's easy to criticize with hindsight. I've redone a couple of boats and looking back there's always something I would have done differently.
What is interesting about this build is that he sold it online with pictures of how it's aged, and it's got more problems than just that fuel tank.
The durabak floor, which the company used as a testimonial in their ads, is a disaster.
The balance of the boat is so completely off with those two 4 strokes hanging off the bracket that the motors are totally corroded up and under the cowlings.
After all of that work, time and money, painting his truck to match and everything the poor guy manages to put about 200 hrs on the boat before selling it.
Jack of all trades, master of none can end in serious disappointment if you're building your "dreamboat". Boats that work properly and look great doing it are no accident.

as a matter of fact,yes I did...

any more questions ??

Yes. Where is Spidercrab when you need him? :D

mr heron
we be bizzy get reddy fur hurricane

meemaw always sed I wuz a misteak but peepaw sed don't
blame him fur what sumone else did

shoot my 20 crabber iz held together wit coal pitch an duck tape

sam

I looked at Sam's profile and I saw where it said I could "befriend" him.

I'm still thinking about that, not sure yet...... :)

We sure miss 'ol Spidercrab!!!

SAM!

This is what happens when understanding and knowledge meet.

Cheers,
GFS

Interesting dialog from the previous posts...

My personal opinion is that for the most part of the active
membership here on CSC that those of us that have under taken
complete restorations hold various other educated professional positions.

Boat maintenance and restoration is just a hobby for us!

I would put the work of Strick, Blue Heron, & myself against
anyone that it is doing it professionally...
Agh yes we do make mistakes..:eek:
That is half the fun in fixing a boo boo..;)

That being said we would hope that those in their chosen positions
in life that they strive to be nothing but the best that they can be..

Oh yeah Sam, glad to see you stopping by and stay safe!

I I consider many here to be true friends. I need to ask more and learn more.

Brother sent me a dive knife. Nice. Hondah carb was only 32 clams sent.
Yum,
GFS

You say "Yum" a LOT. WTF is up with that? Strange dietary habits? Sheep?

Hey, Sam. Welcome back. Good to see you again.

Sc nice
 

I I consider many here to be true friends. I need to ask more and learn more.

Brother sent me a dive knife. Nice. Hondah carb was only 32 clams sent.
Yum,
GFS

Yes just one more since you sent me that PM with your marine certifications. Sorry but I am not one that is easily impressed with certificates. I don't know why you did that because your knowledge about fuel tanks or anything marine related was never questioned. The problem was with you bad mouthing someone that made an honest mistake. So my question to you is.... if you want to make yourself out to be a professional then why cant you at least act like a professional ?

If you want to go kindergarten again and get the last word in then go ahead.....I'm out ;)

Jeeez some people......


Spidey thanks for the resurface. That made the whole thred worth it...

strick

I knew I should have been reading over here, instead of raising a ruckus over on THT.
Now you boys play nice. ;)

I was a chef in a former life. Worked some fine kitchens. Yum.

Made a fried egg sangwich fer breakfeast.

You've got mad skills, Mr Herman. I asked my wife to make me a scrambled egg sandwich with cured spanish chorizo and lake country cheese on goliath rye toast and she said, "make it yourself." Any advice on how to concoct such a culinary extravaganza:confused:

I gotta cook my own too. Buster ain't got hands.:o

Amen Brothah!

There`s an old saying in the restaurant biz.

You`re only as good as your last meal.

I have a shiny diploma that collects dust in a closet.

My first real job was washing dishes for a crazy Italian chef who liked to throw knives.
I was 12 and my first night is a memory etched in stone.

Made this for breakfast

http://i655.photobucket.com/albums/u...psfb46d803.jpg

We have something special here.

Thanks!

Good news = No alligators in the mold.

Bad news = Plug didn't survive the extraction.

Dude, what did you fair that thing with? It peeled off in slabs even with a healthy coating of PVA.

yum yum.

One of these? or an upside down anchor locker mold :)